Analysis and Experimental Investigation of the Light Dimming Effect on Automotive Visible Light Communications Performances

The use of Visible Light Communications (VLC) in vehicular applications has become a major research area due to its simplicity, high performance to cost ratio, and great deployment potential. In this context, this article provides one of the very few analyses and experimental evaluations concerning the integration of a light dimming function in vehicular VLC systems. For this purpose, a vehicle-to-vehicle VLC prototype has been implemented and used to evaluate the systems' communication performances in light dimming conditions, while decreasing the duty cycle from 40% to 1%, and increasing the communication range from 1 to 40-50 m. The experimental results showed that in normal lighting conditions, the VLC technology can easily support low duty cycle light dimming for ranges up to 40 m, while maintaining a 10(-6) BER. Nevertheless, in strong optical noise conditions, when the system reaches its SNR limit, the communication range can decrease by half, whereas the BER can increase by 2-4 orders of magnitude. This article provides consistent evidence concerning the high potential of the VLC technology to support inter-vehicle communication links, even in light dimming conditions.